Study On Fault Area Location And Distance Measurement For Complex Distribution Network

With the improvement of automation and intelligence of distribution network,a large number of automation terminal devices are applied in distribution network,which can measure the voltage and current of distribution network in real time,and provide a basis for the accurate fault location methods.However,due to the large number of branches and nodes in distribution network,the measuring device can not be installed at each node.The existing fault area location methods based on distribution automation will obtain a large fault area.In addition,Most of the distribution network fault distance location algorithms rely on the short circuit iteration calculation or a large number of simulation with different faults to select the most matched fault points for realizing the ranging function.This kind of method is cumbersome and easy to get the false fault points when the measuring points are few,so it is urgent to develop a method that can accurately locate fault area and fault point by using a few measuring points.Firstly,the positive sequence network of fault components is constructed,and a new criterion for fault area location is proposed.Aiming at the problem that the number of measuring points in distribution network is far less than the number of nodes,an underdetermined fault component voltage equation is established,and a method based on Bayesian compressed sensing theory is proposed to solve the underdetermined voltage equation in order to locate the fault area.This method needs few measuring points and is not susceptible to the influence of the false fault points.The properties of node impedance matrix of distribution network are proved,so a fault location method based on absolute value calculation is proposed,which improves the speed and accuracy of calculation and reduces the synchronization requirement of communication between measuring pointsSecondly,the influence of fault type,fault resistance,noise,line parameter error,measurement point distribution,fault initial phase angle and photovoltaic power supply on fault area location method is systematically analyzed,and a multi-node complex distribution network model with distributed generators is established,which verifies the correctness of the analysis of various influencing factors,and finds that the fault area location method proposed in this paper is reasonable,effective,and not affected by fault type,fault resistance,fault initial phase angle,and has a strong ability to withstand noise,line parameter errors.Facing the situation that the photovoltaic power supply is connected to the distribution network,it can also accurately locate the fault area.Finally,on the basis of realizing fault area location,the calculation method of voltage and equivalent impedance of nodes at both ends of fault area is proposed,anda scheme of fault distance measurement based on voltage amplitude information of sparse measuring points is proposed.Based on the multi-node complex distribution network model,the accuracy of the fault distance measurement method is verified.It is found that the fault distance measurement method is not affected by fault type and fault resistance,and has a strong ability to withstand noise.Facing the situation of photovoltaic power connected to the distribution network,it can also accurately locate the fault point.